Shapes & Designs Flashcards
Polygon
A closed figure made up of three or more line segments that only intersect at the vertices.
Regular Polygon
A polygon with all sides of the same length and all the angles are the same.
Irregular Polygon
A polygon that does not have equal sides and equal angles.
Complementary Angles
Two angles whose sum is 90 degrees.
Supplementary Angles
Two angles whose sum is 180 degrees.
Parallel lines
Two lines which will never intersect (cross).
Parallelogram
A quadrilateral with two sets of parallel lines.
Transversal
A line segment that cuts across two or more line segments.
Interior Angles
The inside angles of a polygon. (n-2) x 180
Reflectional Symmetry
a shape with reflectional symmetry has halves that are mirror images of one another.
Rotational Symmetry
A shape with rotational symmetry can be turned about a center point through some angle between 0 and 360 degrees and it will look exactly the same.
Tiling/Tessellation
The covering of a plane surface with geometric shapes without gaps or overlaps.
Trapezoid
A quadrilateral with only one set of parallel lines.
Vertical Angles
A pair of congruent, non-adjacent angles formed by the intersection of two lines.
Rhombus
A quadrilateral with all sides the same length.
Exterior Angle
The outside angles of a polygon formed by one side and an extension of the other side.
What is the angle sum of a triangle?
180 degrees
What is the angle sum of a quadrilateral?
360 degrees
What is the angle sum of a pentagon?
540 degrees
What is the angle sum of a hexagon?
720 degrees
What is the formula for finding the angle sum of any polygon?
(n-2) x 180
Obtuse Angle
Measures more than 90 and less than 180 degrees
Acute Angle
Measures more than 0 and less than 90 degrees
Right Angle
Measures exactly 90 degrees
What do one set of Interior and Exterior Angles of any shape always add to?
180 degrees
What do all the exterior angles of a polygon add to?
360 degrees (1 full turn)
What has to be true of three sides lengths in order to make a triangle?
The sum of the two shortest sides must be larger than the third side.
What has to be true for 4 side lengths to make a quadrilateral?
The sum of the three shorter sides must be greater than the fourth side.
What do adjacent angles in a parallelogram always add to?
180 degrees
Opposite angles in a parallelogram are always?
equal.
